Support structure design optimization for 3D-printed polyetherketoneketone (PEKK) cranial patches

During the 3D printing process, the support structure significantly influences the geometric accuracy, mechanical stability, and material utilization of cranial repair implants. Meanwhile, optimizing the support structure not only enhances the performance and surface quality of the printed parts but also reduces manufacturing costs. In this study, Fused Filament Fabrication (FFF) was employed to fabricate Polyetherketoneketone (PEKK) cranial patches, with a focus on optimizing the design of the support structures. Critical self-supporting angles and maximum printable overhang lengths were experimentally determined, revealing that under the present printing conditions, PEKK exhibits a critical self-supporting angle of 45° and a recommended maximum overhang length of 6 mm. Three typical support configurations—grid, cross, and tree-like—were subjected to finite element analysis under both gravitational and uniformly distributed surface loads. The results demonstrated that tree-like supports not only met the strength and stability requirements, but also offered the highest material utilization efficiency, the smallest contact area with the model, and the greatest ease of removal. Parameter optimization of the tree-like support was further conducted and experimentally validated. In full-scale cranial patch printing, the optimized tree-like support reduced material consumption by approximately 65% and lowered total production costs by about 33% compared with conventional grid supports, while maintaining high dimensional accuracy. This study confirms that tree-like support structures enable high-precision and cost-efficient FFF manufacturing of PEKK cranial patches.